Furnace.



C. S. DRUMMOND.

FUBNAGB. APPLICATION FILED JUNE 13 Patented July 19, 1 910.

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CHARLES SINCLAIR DRUMMOND, Oli LONDON,

ENGLAND.

FURNACE.

Specification of Letters Patent.

Patented July 19, 1910.

Application led June 13, 3.908. Serial No. 438,423.

To all whom it may concern:

Be it known that I, CHARLES SINGLAIR DRUMMoiv-D, subject of the King of Great Britain, residing at No. 23 St. Mary Axe, in the city of London, England, have invented new and useful Improvements in Furnaces, of which the following is a speci fication.

This invention relates to improvements in the construction of furnaces for the combustion of solid fuel on a closed hearth without a fire grate.

On the accompanying drawing are shown as representative examples some forms of a furnace constructed according to the above described invention.

In this drawing z-Figure l is a part plan of a circular furnace. Fig. 2 is a plan of a rectangular furnace. Fig. 3 is a vertical section corresponding to Fig. 2, and :-Fig. 4 shows a modification of construction.

Referring to Figs. l and 3, L -a are a plurality of similar moldings or castings which, when assembled, compose a complete circular wall which surrounds a space for the reception of the fuel, the floor being a closed hearth b formed of refractory material.

Around the outside of the wall a passage c is provided, the boundary on the furnace side consisting of the said wall, the upper boundary being a horizontal flange a] of the elements c and the outer boundary of the passage consisting of the lower portion d of the side of the furnace.

rlhe passage c is in communication with the external atmosphere through the opening e which, by the branch f, leads beneath the foot g of the boiler to which heat is being supplied by the furnace.

From the upper side of the passage c the air fiows to the furnace through a series of tubular downward extending channels 7L formed in locally thickened portions of the wall of the elements a, the thickened portions protruding into the furnace and presenting an augmented surface for the reception of heat which is conducted through the metal and heats the incoming air. The tubular channels extend downward to a comparatively short distance from the furnace-hearth and thus the air is supplied well beneath the burning fuel through which it passes upward and emerges in the condition of burnt gases through the flue-passage z'.

In furnaces which are wide or of large diameter some of the air admission channels ,7L may be prolonged so as to conduct some of the air toward the center of the bed of fuel as by laying an inverted piece, of channel section, on the hearth of the furnace as indicated at k1 in Fig. l.

To unite together in a secure and fluidtight manner the abutting surfaces of the elements c, grooves of dove-tail section are provided into which a prism of double dovetail section can be dropped and the remainder of the grooves filled with lire-clay. The joint between the flange al and the furnace plate is also rendered stanch by means of hre-clay or asbestos as indicated at 7e.

Fig. et shows in section a modified form of construction in which both the inner and the outer walls of the passage c, and also the crown thereof, are east integrally, tubular channels m being formed at intervals wit-hin the thickness of the wall next the fire. A ring of such a section or a plurality of united elements of such a section are supported on a ring-base n so dimensioned that the orifices at the lower extremity of the tubular channels m overhang the base a and provide an annular passage around the inside of the furnace beneath the foot of the wall for the more freely extended distribution of the entering air to the burning fuel.

rlhe boiler rests on the integral or built up ring which composee the furnace, an internal flange o, extending upward, serves to center the furnace relatively to the boiler and protect the heads of the rivets from the heat of the fire the space between the flange 0 and the furnace-plate CZ being filled with asbestos or re-clay- Vith this last described construction the examination and repair of the interior of the furnace will be facilitated. For by lifting, the boiler the short distance of the height of the flange 0, the furnace ring can be withdrawn laterally apart from the boiler.

l claim:

l. In a furnace, a closed hearth, a wall surrounding the space for the reception of fuel on said hearth, said wall being surrounded by a passage in communication with the atmosphere and having channels formed therein leading from the upper portion of said passage to the interior of the furnace and terminating Within the fuel space slightly above said hearth.

2. In a furnace, a closed hearth, a wall surrounding the space for the reception of fuel on said hearth, said wall being surrounded by a passage in communication with the atmosphere and having' channels formed therein leading from the upper portion of said passage to the interior of the furnace and terminating within the fuel space slightly above said hearth, the walls of said channels protruding into the interior of the furnace.

3. In a furnace, a closed hearth, a wall surrounding the space for the reception of fuel on said hearth, said wall being surrounded by a passage in communication with a conduit leading om the atmosphere thereto and having channels formed therein leading' from the upper portion of said passage to the interio1 of the furnace and terminating within the fuel space slightly above said hearth.

4. An element of a furnace, comprising a wall, an upper flange on the outside of said wall, said wall having tubular channels leading from beneath the said flange downward and forming projections on the fire-exposed l r l l said channels opening side of said wall,

said wall adjacent its on the inner side of lower end.

5. An element of a furnace, comprising a wall, an upper flange on the outside of said. wall, said Wall having tubular channels leading from beneath the said flange downward and forming projections on the fireexposed side of said wall said channels opening on the inner side of said wall adjacent its lower end, and the ends of said element being formed with undercut grooves.

6. In a furnace, a closed hearth, a plurality of elements assembled as a complete wall around the space for the reception of fuel on said hearth, an upper outwardly directed fiange on each of said elements, locally thickened portions on the fire-exposed side of said elements having tubular channels leading from beneath said flange downward, and an outer wall so surrounding said assembled elements and abut-ting against said flange as to inclose an annular space in communication with the atmosphere.

In testimony whereof I have signed my name to this specification in the presence of two subscribing' witnesses.

CHARLES SINCLAIR DRUMMOND. l'Vitnesses F. YV. LANE, H. D. JAMESON. 

